#pragma once

#include <iostream>
#include <string>
#include <vector>
#include <mutex>
#include <jsoncpp/json/json.h>

#include "../comm/util.hpp"
#include "../comm/log.hpp"
#include "../comm/httplib.h"
#include "oj_model.hpp"
#include "oj_view.hpp"


namespace ns_control
{
    using namespace std;
    using namespace ns_log;
    using namespace ns_util;
    using namespace ns_model;
    using namespace ns_view;
    using namespace httplib;


    class Machine
    {
    public:
        std::string ip;
        int port;
        uint64_t load;
        std::mutex* mtx;
        Machine():ip(""),port(0),load(0),mtx(nullptr)
        {

        }
        void IncLoad()
        {
            if(mtx)
            {
                mtx->lock();
            }
            load++;
            if(mtx)
            {
                mtx->unlock();
            }
        }
        void DecLoad()
        {
            if(mtx)
            {
                mtx->lock();
            }
            load--;
            if(mtx)
            {
                mtx->unlock();
            }
        }
        void ResetLoad()
        {
            if(mtx)
            {
                mtx->lock();
            }
            load--;
            if(mtx)
            {
                mtx->unlock();
            }
        }
        uint64_t Load()
        {
            uint64_t _load = 0;
            if(mtx)
            {
                mtx->lock();
            }
            _load = load;
            if(mtx)
            {
                mtx->unlock();
            }
            return _load;
        }
    };

    const std::string service_machine = "./conf/service_machine.conf";

    class LoadBlance
    {
    private:
        std::vector<Machine> machines;
        std::vector<int> online;
        std::vector<int> offline;
        std::mutex mtx;
    public:
        LoadBlance()
        {
            assert(LoadConf(service_machine));
            LOG(INFO) << "加载" << service_machine << " 成功" << "\n";
        }
        bool LoadConf(const std::string& machine_conf)
        {
            std::ifstream in(machine_conf);
            if(!in.is_open())
            {
                LOG(FATAL) << " 加载: " << machine_conf << "失败" << "\n";
                return false;
            }
            std::string line;
            while(std::getline(in,line))
            {
                std::vector<std::string> tokens;
                StringUtil::SplitString(line,&tokens,":");
                if(tokens.size() != 2)
                {
                    LOG(WARNING) << " 切分 " << line << "失败" << "\n";
                    continue;
                }
                Machine m;
                m.ip = tokens[0];
                m.port = atoi(tokens[1].c_str());
                m.load = 0;
                m.mtx = new std::mutex();
                online.push_back(machines.size());
                machines.push_back(m);
            }
            in.close();
            return true;
        }
        bool SmartChoice(int* id,Machine** m)
        {
            mtx.lock();
            int online_num = online.size();
            if(online_num == 0)
            {
                mtx.unlock();
                LOG(FATAL) << "所有的后端编译主机已经离线" << "\n";
                return false;
            }
            *id = online[0];
            *m = &machines[online[0]];
            uint64_t min_load = machines[online[0]].Load();
            for(int i = 1;i < online_num;i++)
            {
                uint64_t curr_load = machines[online[i]].Load();
                if(min_load > curr_load)
                {
                    min_load = curr_load;
                    *id = online[i];
                    *m = &machines[online[i]];
                }
            }
            mtx.unlock();
            return true;
        }
        void OfflineMachine(int id)
        {
            mtx.lock();
            for(auto iter = online.begin();iter != online.end();iter++)
            {
                if(*iter == id)
                {
                    machines[id].ResetLoad();
                    online.erase(iter);
                    offline.push_back(id);
                    break;
                }
            }
            mtx.unlock();
        }
        void OnlineMachine()
        {
            mtx.lock();
            online.insert(online.end(),offline.begin(),offline.end());
            offline.erase(offline.begin(),offline.end());
            mtx.unlock();
            LOG(INFO) << "所有的主机又上线了" << "\n";
        }
        void ShowMachines()
        {
            mtx.lock();
            std::cout << "当前在线主机列表:";
            for(auto& id:online)
            {
                std::cout << id << " ";
            }
            std::cout << std::endl;

            std::cout << "当前离线主机列表:";
            for(auto& id:offline)
            {
                std::cout << id << " ";
            }
            std::cout << std::endl;
            mtx.unlock();
        }
    };


    class Control
    {
    private:
        Model _model;
        View _view;
        LoadBlance _load_blance;
    public:
        Control()
        {

        }
        void RecoveryMachine()
        {
            _load_blance.OnlineMachine();
        }

        bool AllQuestions(std::string* html)
        {
            vector<Question> all;
            if(_model.GetAllQuestions(&all))
            {
                _view.AllExpandHtml(all,html);
            }
            else
            {
                *html = "获取题目失败,形成题目列表失败";
                return false;
            }
            return true;
        }
        bool OneQuestion(const std::string& number,std::string* html)
        {
            Question q;
            if(_model.GetOneQuestion(number,&q))
            {
                _view.OneExpandHtml(q,html);
            }
            else
            {
                *html = "指定题目: " + number + " 不存在!";
                return false;
            }
            return true;
        }

        void Judge(const std::string& number,const std::string& in_json,std::string* out_json)
        {
            Question q;
            _model.GetOneQuestion(number,&q);

            Json::Reader reader;
            Json::Value in_value;
            reader.parse(in_json,in_value);
            std::string code = in_value["code"].asString();

            Json::Value compile_value;
            compile_value["input"] = in_value["input"].asString();
            compile_value["code"] = code + "\n" + q.tail;
            compile_value["cpu_limit"] = q.cpu_limit;
            compile_value["mem_limit"] = q.mem_limit;

            Json::FastWriter writer;
            std::string compile_string = writer.write(compile_value);

            while(true)
            {
                int id = 0;
                Machine* m = nullptr;
                if(!_load_blance.SmartChoice(&id,&m))
                {
                    break;
                }
                LOG(INFO) << " 选择主机成功,主机id: " << id << "详情: " << m->ip << ":" << m->port << "\n";
                Client cli(m->ip,m->port);
                m->IncLoad();
                if(auto res = cli.Post("/compile_and_run",compile_string,"application/json;charset=utf-8"))
                {
                    if(res->status == 200)
                    {
                        *out_json = res->body;
                        m->DecLoad();
                        LOG(INFO) << "请求编译和运行服务成功..." << "\n";
                        break;
                    }
                    m->DecLoad();
                }
                else
                {
                    LOG(ERROR) << "当前请求的主机id: " << id << "详情: " << m->ip << ":" << m->port << "可能已经离线" << "\n";
                    _load_blance.OfflineMachine(id);
                    _load_blance.ShowMachines();
                }
            }
        }
    };
}
